Allison Rae

Paramount Industries

Rhode Island School of Design ID 87’

Prototyping Overview

1

Prototyping for Mechanical Parts

2

Paramount IndustriesStarted as prototyping vendor,

then added:• Industrial Design• Product Engineering• Product verification• Breadboard models• Computer Animations• Graphic Design

3

Rapid Prototyping Chart- 3D data required Common uses

Material Description

Cost for Ball Tray

Delivery for Ball Tray Tolerance Layer height

Surface scale 1-4 fine to coarse

SLA Stereo Lithography Apparatus liquid

photopolymer0.002- 0.005

standard appearance models, casting masters

rigid $300 2 days +/-.002 +/-.005

0.005 1

flex resin more durable appearance models

flexible $300 2 days +/-.002 +/-.005

0.005 1

SLS Selective Laser Sintering thermoplastic

powderNylon living hinges, snap fits,

functional modelsnylon,

polyamide$250 2 days +/-.007 0.004 2

Glass Filled Nylon extremely durable 33% glass filled $250 2 days +/-.007 0.004 2Somos, elastomeric soft touch parts like Santoprene $200 2 days +/-.007 0.004 2Castform investment cast

mastersstyrene/wax $300 4 days +/-.007 0.004 2

FDM, Fuse Deposition Modeling modeling

filamentABS replicate ABS thermoplastic $250 2days +/-.005

+/-.0100.005 - 0.016 4

Polycarbonate replicate PolyCarb thermoplastic $250 2 days +/-.005 +/-.010

0.01 4

ZCorp form study models, colors available

starch $150 2 days +/-.005 +/-.010

0.003 - 0.010 3

4

Rapid Prototyping- SLS

5

Other Prototyping Methods Common uses Benefits Input/ Process Delivery Tolerance

Material characteristics Quantities

Fabricationhand made models form study models, wax

models, breadboard models,

LooksLike/WorksLike models

achieve geometry too complex for

3D CAD, multiple materials

napkin sketch to part drawings

complexity dependant

as needed limitless 1-5

Urethane CastingsSilicone RTV Molds, cast urethane resins

sales samples, LL/WL models,

replicates production, fast,

inexpensive, color

pattern/ cast silicone

1-2 weeks +/- .001- .100 in/in

rigid, flexible, clear, hollow, insert and

co-molding, production like

materials

10 - <50

ThermoformingSheet thermoplastics wall thickness housings,

blister packagingquick, molds and

produce many parts

pattern or mold .5-2 weeks +/-.010- .060 simple geometry, opaque and clear

prototype & production

Investment Castingmetal cast process engineering check models production

materialspattern 2-4 weeks material

dependantmetals, zinc to titanium

prototype & production

CNC MachiningComputer numeric controlled machining

engineering check models, strong parts

production materials

part drawings, 3D data

geometry dependant

limitless all plastic and metals

prototype & production

6

Wax Sculpting

7

Fabricated Model

8

Cast Urethane Samples

9

Vacuum Forming

Pattern Part

10

Investment Casting

1. Wax Pattern is created (positive)

2. Pattern is dipped in ceramic slurry and then fine sand

3. Assembly is de-waxed by applying heat

4. Molten metal is poured into shell

• Creates metal parts that are difficult or impossible to machine

11

CNC Machining

12

Prototype Tooling Uses Benefits Input/ Process Delivery ToleranceMaterial

characteristics QuantitiesAluminum test production

materials and part geometry

faster and less expensive than

production tooling

2D, 3D data, Pattern/ CNC

EDM, pantograph

1-10 weeks +/- .002 in/in medium temp thermoplastics

25K- <50k

Pre-Hard Steel (P-20) same as aluminum, longer tool life, more complex tools, wider

range of materials

same as aluminum

2D, 3D data, Pattern/ CNC

EDM, pantograph

1-10 weeks production all thermoplastics w/ glass

100K - <250K

Production Tooling Uses Benefits Input/ Process Delivery ToleranceMaterial

characteristics QuantitiesHardened Steel, Multi Cavity all materials large quantities,

lower part cost2D, 3D data,

Pattern/ CNC, EDM,

pantograph

complexity dependant

production all thermoplastics w/ glass

1M +

13

Prototype Tooling

14

Prototype ToolingAluminum or Pre-hardened Steel

• Process, machined, EDM• Tool Life: 12 - 250,000• Benefits:

– Low volume production– High accuracy– Most Thermoplastics

• Delivery: 4-6 weeks

15

Types of Models

Verification Model SLS

Foam Study Model

Clinical Trial Prototype, Autoclavable GE Ultem: CAM/CNC

• ConceptFunctional, bread boards, form

• Looks like modelPhotography, presentations

• Looks like/ works likeSales samples, market testing

• Tooling patterns• Engineering check models

Confirm geometry, test production materials,prove function

16

Concept Models• Purpose; Study scale, develop form, explore

ergonomics• Input; Sketches, verbal description, 3D data• Process and materials;

– Hand build, foam, insulation or urethane, foam core, clay, cannibalize existing products

– Rapid prototyping, Z Corp, SLS, SLA

– Machining, block, tube and sheet stock

• Tolerances; Not important• Quantity; Usually ONE

17

Concept Model

Handmade foam model to explore form

Chosen for speed, 3D data not available

18

Concept Breadboard Model

Fabricated by hand

Chosen to accommodated many materials19

Looks Like Model (LL Model)

• Purpose, same as above including functional requirements.– Draft included only as it effects the performance.– Cored for function only.– Materials used to replicate production material performance.– Includes batteries, electronics, springs, LEDs .

• Process and materials.– Rapid prototypes, SLS, SLA.– Castings/ urethane, silicone.– Machining/ stock plastic.

• Tolerances, tight as needed.• Quantity, 1-12.

Looks Like/ Work Like Model (LL/WL)

• Purpose, aesthetic– Shows surface finish; color, clear parts, labels, tactile materials

20

Looks Like/ Works Like

SLA master RTV Mold, Cast Urethane

Chosen for production like resins

21

LooksLike/WorksLike

Urethane Casting from SLA master and RTV moldsChosen to replication production parts in accuracy, color and texture

22

Tooling Pattern

Fabricated by hand

Chosen to accommodate highly complex geometry

23

Engineering Models• Purpose, confirm geometry, test production

materials, review function• Input, 3D data, detailed part drawings• Process and materials

– Rapid prototyping/ SLS, FDM, SLA– CNC or machined/ production materials– Prototype molds/ production materials

• Tolerances, critical• Quantity, usually ONE

24

Engineering Model

Rapid Prototype, SLA

Chosen for accuracy and speed

25

Engineering Model

Rapid Prototype, SLS Glass Filled Nylon

Chosen for durability to withstand testing

26

Prototype Molded Parts

Aluminum Prototype Injection Mold

Chosen to prove material adhesion and for market testing

27

Qualifying your prototyping needs• What type of model do you need?• What type of input do you have?

– sketches, control drawings, 3D data • Is the production material required?• What are the tolerances?• How many do you need?• When do you need it?• Are you working within a budget?

28

PD EfficiencyThe right questions will improve PD efficiency• Identify risk in your project• Formulate questions, that if answered, will

reduce/eliminate risk• Use models/prototypes to get the answers• Target individual questions at first.

Repeat as necessary.Can use other tools to answer questions.

29

MIT OpenCourseWarehttps://ocw.mit.edu

15.783J / 2.739J Product Design and DevelopmentSpring 2006

For information about citing these materials or our Terms of Use, visit: https://ocw.mit.edu/terms.